Measuring health of a connector member of a robotic surgical system

ABSTRACT

A robotic surgical system includes a controller, a surgical instrument supporting an end effector, and one or more connector members coupled to the end effector and movable to operate the end effector. Memory is operably coupled to the controller and is configured to maintain reference data of the one or more connector members. A sensor is secured to the one or more connector members and is disposed in electrical communication with the controller. The sensor is configured to register real-time data of the one or more connector members and communicate the real-time data to the controller. The controller is configured to compare the real-time data to the reference data and provide an output signal in response to a comparison of the real-time data to the reference data. A pair of connector members may be coupled to the end effector to impart three outputs.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a U.S. National Stage Application filed under 35U.S.C. § 371(a) of International Patent Application Serial No. PCT/U.S.2016/021331, filed Mar. 8, 2016, which claims the benefit of andpriority to U.S. Provisional Patent Application Ser. No. 62/184,305,filed Jun. 25, 2015, and U.S. Provisional Patent Application Ser. No.62/130,672, filed Mar. 10, 2015, the entire disclosures of which areincorporated by reference herein.

TECHNICAL FIELD

The present disclosure relates to robotics, and more specifically torobotic surgical devices and/or systems for performing endoscopicsurgical procedures and methods of use thereof.

BACKGROUND

Robotic surgical systems have been used in minimally invasive medicalprocedures. Although robotic surgical systems provide many benefits suchas increased accuracy and expediency, one drawback is a lack of orlimited force feedback. Independent of surgical training, force feedbackenables more precise dissection with lower applied forces and fewererrors.

Some robotic surgical systems include a console supporting a robot arm,and at least one end effector such as forceps or a grasping tool that ismounted to the robot arm via a wrist assembly. During a medicalprocedure, the end effector and the wrist assembly are inserted into asmall incision (via a cannula) or a natural orifice of a patient toposition the end effector at a work site within the body of the patient.

Connector members such as cables extend from the robot console, throughthe robot arm, and are connected to the wrist assembly and/or endeffector. In some instances, the connector members are actuated by meansof motors that are controlled by a processing system including a userinterface for a surgeon or clinician to be able to control the roboticsurgical system including the robot arm, the wrist assembly and/or theend effector.

Generally, these connector members have limited lifespans and a tendencyto fail or become un-usable after a certain number of uses, which mayvary, depending upon the duration and/or stress each use imposes onthese connector members.

SUMMARY

Accordingly, there is a need for robotic surgical systems that providereal-time information regarding connector members for determining healthof these connector members and for improving failure predictionaccuracy. It would also be desirable to monitor these connector membersfor establishing force feedback from the end effector. In this regard, aclinician would be able to advantageously determine, for example,grasping forces of the end effector to improve precision and limiterrors.

In one aspect, the present disclosure is directed to a robotic surgicalsystem including a controller and a surgical instrument with a shaftassembly supporting an end effector. One or more connector members arecoupled to the end effector and movable to operate the end effector. Oneor more sensors are operably coupled to one or more of the connectormembers and disposed in electrical communication with the controller formonitoring the connector members.

In one embodiment, the end effector provides a wristed surgical devicethat uses differential connector member tension on four connector memberends (of two connector members) to drive three primary motion outputs:pitch, yaw, and jaw motion. The connector members may be routed around aset of idler pulleys that pivot about a pitch axis and about another setof idler pulleys that are located proximal to the pitch axis. In someembodiments, all idler pulleys may be located along the shaft assembly.With the jaw and pivot axis coincident and extending through a proximalportion of jaw members of the end effector, this arrangementadvantageously provides a short wrist length as compared to devices thatprovide idler pulleys between the pitch and yaw axes. Pitch, yaw, andgrasping/dissecting and any combinations of these motions are achievedthrough pulling and/or releasing different combinations of the connectormember ends.

By comparison to a more traditional end effectors including three closedloop connector members, each of which are positioned for effectuatingone of the three outputs (pitch, yaw, and grasp), respectively, thedifferential drive embodiment is simplified in that it only requires twoopen looped connector members (four ends) to drive the three outputs(pitch, yaw, and grasp). Further, given that the two connector membersof the differential drive embodiment are open looped connector membersas compared to the more traditional closed loop three connector memberend effectors, the differential drive embodiment provides adjustableconnector member tension. More specifically, the tension on theconnector members of the differential drive embodiment can be relaxedwhen the surgical instrument is not in use so as to prevent continuousload on the components (cables, pulleys, tabs, etc.) of the surgicalinstrument, thereby improving longevity of the surgical instrument andits components. In addition, the open looped connector members enableactive monitoring, for example, with the sensors, of output loads, suchas grasping force, torque around the pitch axis, and torque around theyaw axis.

Minimized wrist length also advantageously enables greater pitch and/oryaw movement while minimizing instrument shaft motion, which, in turn,enables instruments to be placed closer together and/or enables fastermanipulation of the end effector.

The robotic surgical system may include memory operably coupled to thecontroller and configured to maintain reference data of one or more ofthe connector members. The reference data can include one or more of: aproperty of the connector members; a force applied to the connectormembers; a number of uses of the connector members; or an age of theconnector members.

The sensors may be configured to register real-time data of theconnector members and communicate the real-time data to the controller.In some embodiments, the sensors include a force sensor, a positionsensor, or combinations thereof.

The controller is configured to compare the real-time data to thereference data and provide an output signal in response to a comparisonof the real-time data to the reference data. The controller may beoperably coupled to one or more motors. The controller can be configuredto communicate with the motors to adjust an amount of tension in theconnector members in response to the output signal. In some embodiments,the controller is configured to provide the output signal in response toone or more events. The event(s) can include one or more of: a first useof the surgical instrument, a use of the surgical instrument subsequentto the first use of the surgical instrument, a user initiated command,or an expiration of at least one time period.

In some embodiments, the robotic surgical system includes a driveassembly having a drive member and a drive tab supported on the drivemember. The drive member is coupled to a motor disposed in electricalcommunication with the controller. The one or more connector members aresecured to an instrument tab. The drive tab and the instrument tab areengagable to manipulate the end effector as the drive tab moves alongthe drive member in response to actuation of the motor. The drive memberand the drive tab may be threadably engaged. The drive member may berotatable to move the drive tab axially along the drive member.

According to another aspect, a method of determining health of one ormore connector members of a robotic surgical system is provided. Theconnector members are operably coupled to an end effector of the roboticsurgical system and movable to operate the end effector. The methodincludes storing reference data of one or more of the connector membersprior to an initial use of one or more of the connector members. Theconnector members have an initial health. The method includes measuringreal-time data of the connector members subsequent to the initial use ofone or more the connector members, and comparing the reference data ofthe connector members with measured real-time data of the connectormembers to determine the real-time health of the connector members.

In some embodiments, the method involves measuring force applied to theat least one connector members. In certain embodiments, the methodincludes calibrating tension in the connector members in response tochanges in the real-time data of the connector members. The method mayinvolve automating an output signal indicative of real-time data of theconnector members in response to one or more events. The method caninvolve receiving an input signal indicative of a user input to initiatean output signal indicative of real-time data of the connector members.The method can include registering a failure of the connector membersand providing an output signal indicative of the failure.

According to yet another aspect, a robotic surgical system includes acontroller, a first connector member, a second connector member, an endeffector, and one or more motors operably coupled to the controller.

The one or more motors are operably coupled to the first and secondconnector members and are actuatable to move the first and secondconnector members.

The end effector includes a first jaw member and a second of jaw member.The first jaw member includes a first jaw pulley and a first graspingportion extending from the first jaw pulley. The first jaw pulley may beintegrally formed with the first grasping portion and the second jawpulley may be integrally formed with the second grasping portion. Thesecond jaw member includes a second jaw pulley and a second graspingportion extending from the second jaw pulley. The first connector memberis secured to the first jaw pulley and the second connector member issecured to the second jaw pulley. The first and second connector membersare movable to move the first and second jaw members between threedifferent outputs.

In some embodiments, the first and second jaw pulleys are coupled to aclevis mounted to a set of idler pulleys. The first and second connectormembers are routed around the set of idler pulleys and the first andsecond jaw pulleys.

The robotic surgical system may include a robotic arm supporting a driveunit. The drive unit includes a drive assembly having one or more drivemembers and one or more drive tabs supported on the drive members. Thedrive members are coupled to the motors. One or both of the first andsecond connector members is secured to one or more instrument tabs. Thedrive tabs and the instrument tabs are engagable to manipulate the endeffector as the drive tabs move along the drive members in response toactuation of the motors. In some embodiments, the drive members and thedrive tabs are threadably engaged. The drive members may be rotatable tomove the drive tabs axially along the drive members.

Further details and aspects of exemplary embodiments of the presentdisclosure are described in more detail below with reference to theappended figures.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present disclosure are described herein withreference to the accompanying drawings, wherein:

FIG. 1A is a schematic illustration of a medical work station andoperating console in accordance with the present disclosure;

FIG. 1B is a schematic, perspective view of a drive unit and anattaching device coupled to a robot arm of the medical work station ofFIG. 1A;

FIG. 2 is a perspective view of an end effector, according to anembodiment of the present disclosure, for use in the medical workstation of FIG. 1A, illustrating a jaw assembly thereof in a closedcondition;

FIG. 3 is a perspective view of the end effector of FIG. 2 illustratingthe jaw assembly thereof in an open and articulated condition, andillustrating a wrist assembly thereof in an articulated condition;

FIG. 4A is a flow chart illustrating a method for maintainingpredetermined tension on a connector member of a robotic surgicalsystem;

FIG. 4B is a flow chart illustrating a method for determining health ofa connector member of a robotic surgical system;

FIG. 5 is a perspective view of another embodiment of an end effectorfor use in the medical work station of FIG. 1A;

FIG. 6A is a perspective view of the end effector of FIG. 5 shown in astraight configuration with jaw members thereof in a closedconfiguration;

FIG. 6B is a perspective view of the end effector of FIG. 5 shown in apitched configuration with the jaw members thereof in the closedconfiguration;

FIG. 6C is a perspective view of the end effector of FIG. 5 shown in ayawed configuration with the jaw members thereof in the closedconfiguration;

FIG. 6D is a perspective view of the end effector of FIG. 5 shown in thestraight configuration with the jaw members thereof in an openconfiguration; and

FIGS. 7A and 7B are graphical depictions of grasping force dataestablished with respect to the end effector of FIG. 5.

DETAILED DESCRIPTION

Embodiments of the present disclosure are described in detail withreference to the drawings, in which like reference numerals designateidentical or corresponding elements in each of the several views.

Referring initially to FIG. 1A, a medical work station is showngenerally as work station 1 and generally includes a plurality of robotarms 2, 3; a controller/control device 4; and an operating console 5coupled with controller 4. Operating console 5 includes a display device6, which is set up in particular to display three-dimensional images;and manual input devices 7, 8, by means of which a person (not shown),for example a surgeon, is able to telemanipulate robot arms 2, 3 in afirst operating mode, as known in principle to a person skilled in theart.

Generally, each of robot arms 2, 3 includes a plurality of members,which are connected through joints, and an attachment device 9, 11, towhich may be attached, for example, a surgical tool or surgicalinstrument 20 supporting an end effector 100.

Work station 1 is configured for use on a patient 13 lying on a patienttable 12 to be treated in a minimally invasive manner by means of endeffector 100. Work station 1 may also include more than two robot arms2, 3, the additional robot arms likewise being connected to controller 4and being telemanipulatable by means of operating console 5. One or moresurgical instruments 20 may be attached to the additional robot arm.

Reference may be made to U.S. Patent Publication No. 2012/0116416, filedon Nov. 3, 2011, entitled “Medical Workstation,” the entire contents ofwhich are incorporated herein by reference, for a detailed discussion ofthe construction and operation of work station 1.

FIG. 1B shows an exemplary attachment device 9 having a drive unit 14coupled thereto. Drive unit 14 and/or attachment device 9 may bedirectly and/or indirectly attached to, and/or integrally formed with,one of robot arms 2, 3. For example, in some instances, drive unit 14 isdirectly attached to one of robot arms 2, 3 and attachment device 9 isindirectly attached to one of robot arm 2, 3 while attachment device 9is coupled to drive unit 14. In certain instances, attachment device 9is directly attached to one of the robot arms 2, 3 and drive unit 14 isindirectly attached to robot arm 2, 3 while drive unit 14 is coupled toattachment device 9. In some instances, both attachment device 9 anddrive unit 14 are directly attached to one of robot arms 2, 3.

Drive unit 14 includes a drive assembly 15 having one or more motors 16and one or more drive members 17 coupled to the one or more motors 16.Motor 16 is electrically coupled to controller 4 and operable to impartmovement (e.g., rotational movement) to drive member 17. In someembodiments, drive member 17 is a lead screw. One or more drive tabs 18are mounted to each drive member 17 and movable there along. Asillustrated by arrows “A1,” drive tab 18 is movable relative drivemember 17 in an axially direction (e.g., along the z-axis) in responseto rotational movement of drive member 17 in clockwise and/orcounterclockwise directions as illustrated by arrows “A2.” In someembodiments, drive tab 18 is a split nut drive tab.

Drive tab 18 may be threadably coupled to drive member 17 to effectuatemovement of drive tab 18 relative drive member 17. Drive tab 18 and/ordrive member 17 may include any suitable threading configuration. Forexample, one or more of the threads of drive tab 18 and/or drive member17 can have any suitable shape, diameter, pitch, direction/orientation,etc. In some embodiments, drive member 17 may include multiple sets ofthreads, each set of threads being threaded in an opposite direction ascompared to an adjacent set of threads. In certain embodiments, each setof threads is configured to engage a different drive tab 18 to impartapproximating and/or unapproximating movement between multiple drivetabs 18.

Drive tab 18 includes a force sensor 19 a (e.g., a transducer or thelike) operatively coupled to controller 4 and configured to determineapplied force. Drive member 17 supports a position sensor 19 boperatively coupled to controller 4 and configured to determine one ormore positions of one or more components (e.g., drive tab 18) of driveassembly 15 relative to other components thereof (e.g., drive member17). For example, position sensor 19 b is configured to measure aposition and/or movement of output of motor 16, drive member 17, and/ordrive tab 18.

As seen in the exemplary embodiment shown in FIG. 1B, drive unit 14couples to surgical tool 20 (see FIG. 1A) or instrument such as surgicalinstrument 20. Surgical instrument 20 includes one or more instrumenttabs 22 movably mounted on one or more supports or rails 24. Forexample, instrument tab 22 can be axially movable along rails 24 in thez-direction as indicated by arrows “A3.” One or more connector members26 are coupled to instrument tab 22 that extend along a shaft assembly21 of surgical instrument 20 to end effector 100 thereof foreffectuating movement of end effector 100 and/or portions thereof inresponse to movement of the one or more connector members 26. Connectormembers 26 may include cables, rods, etc. Additionally, and/oralternatively, connector members 26 can be moved for imparting forces toend effector 100, for example, to fire end effector (e.g., staples,clips, etc.).

Controller 4 may control current applied to motor 16 during a surgicalprocedure. The current supplied to motor 16 may be adjusted to movedrive member 17 and drive tab 18 so that drive tab 18 pushes against andmoves a corresponding instrument tab 22 of surgical instrument 20 in thesame z-direction to move a component of surgical instrument 20 such asend effector 100 via connector member 26. In the example shown in FIG.1B, each connector member 26 in surgical instrument 20 is attached atone end to a respective instrument tab 22 and at an opposite end to arespective portion of end effector 100. Each connector member 26 isconnected to a different portion of end effector 100 in order to causedifferent movements of the end effector 100 (e.g., articulation,rotation, open/close jaw members thereof, etc.) in response to movementof respective instrument tabs 22 via corresponding drive tabs 18 and/ormotors 16 of drive unit 14.

A method for maintaining predetermined tension on a connector of arobotic surgical system is shown generally in FIG. 4A. Referring alsoFIG. 1B, the condition of connector member 26 may be measured using datafrom position sensor 19 b and/or force sensor 19 a. As part of aninitial calibration, motor 16, drive member 17, and/or drive tab 18 maybe driven into an initial position. This initial position may bereferred to a zero position. Motor 16 may then be actuated to move theoutput of motor 16, drive member 17, and/or drive tab 18 away from thezero position. Position sensor 19 b may measure an amount of movement ofthe output of motor 16, drive member 17, and/or drive tab 18 away fromthe zero position. Position sensor 19 b may continue to measure thismovement at least until force measured at force sensor 19 a exceeds apredetermined threshold. When the force measured at force sensor 19 aexceeds a predetermined threshold, a total amount of movement from thezero position may be recorded as a reference condition of connectormember 26.

The predetermined force threshold may vary in different situations. Insome instances, the predetermined force threshold may be a fixed valuethat is not customized for different applications. In other instances,the predetermined force may vary for different surgical instruments. Forexample, the predetermined force may be selected to correspond to anamount of force needed to be applied on instrument tab 22 to fullytension connector member 26 without moving a component coupled thereto(such as end effector 100). In other instances, different criteria maybe used to select the predetermined force.

Once the reference condition of connector member 26 is the determined,subsequent changes in condition of connector member 26 may be comparedto the reference condition. To measure subsequent changes in theconnector member 26 condition, the output of motor 16, drive member 17,and/or drive tab 18 may be moved into the zero position. Motor 16 maythen be actuated to move the output of motor 16, drive member 17, and/ordrive tab 18 away from the zero position. Position sensor 19 b maymeasure an amount of movement of the output of motor 16, drive member17, and/or drive tab 18 away from the zero position. Position sensor 19b may continue to measure the movement at least until the force measuredat force sensor 19 a exceeds a predetermined threshold. When the forcemeasured at force sensor 19 a exceeds a predetermined threshold, thetotal amount of movement from the zero position may be recorded as anupdated condition of connector member 26. The updated condition ofconnector member 26 may then be compared to the reference condition ofconnector member 26 to identify a change in the condition of connectormember 26.

Connector member 26 may stretch out under high tension or otherwisedeform over time as connector member 26 is used. As connector member 26stretches out or otherwise deforms, the distances that drive tab 18 andinstrument tab 22 may need to be moved to set a particular connectormember 26 tension in connector member 26 corresponding to thepredetermined threshold measured at force sensor 19 a may also change.The greater the deformity in connector member 26, the more drive tab 18and instrument tab 22 may need to be moved. If the position in theupdated condition differs from that in the reference condition by morethan a predetermined amount, then different actions may be taken. Insome instances, if identified change in the condition of connectormember 26 exceeds a threshold then an initial indication may presentedto alert a person that connector member 26 may need to be replaced. Insome instances, if the change in condition exceeds a second thresholdthen the work station 1 may indicate that the connector member life hasbeen exceeded and/or prevent the use of the surgical instrument 20containing connector member 26. In certain instances, the updatedcondition and/or reference condition may be compared to a set of knownvalues to identify an estimated remaining useful life/health ofconnector member 26. In some instances, dates that the updated conditionand the reference condition were measured along with recorded values ofthe updated condition and reference condition may be compared to a setof known values to identify an estimated end of life date for replacingconnector member 26. In certain instances, different actions and/or twoor more of the aforementioned actions may be taken.

As seen in FIGS. 2 and 3, end effector 100 can include a jaw assembly120 connected to a wrist assembly 110 and one or more connector members26 for moving (e.g. pivoting/articulating/rotating/opening/closing) jawassembly 120 about/relative to longitudinal axes such as long axes“X1-X1” and/or “X2-X2” and/or about/relative to pivot axes such as pivotaxes “A-A” and/or “B-B.” Wrist assembly 110 couples jaw assembly 120 toa robot arm such as robot arms 2, 3.

Reference may be made to International Application No. PCT/U.S.2014/61329, filed on Oct. 20, 2014, entitled “Wrist and Jaw Assembliesfor Robotic Surgical Systems,” the entire content of which isincorporated herein by reference, for a detailed discussion of theconstruction and operation of end effector 100.

In use, as connector members 26 are moved, connector members 26 effectoperation and/or movement of each end effector 100 of the surgicalinstrument (see, e.g., FIGS. 2 and 3). It is contemplated thatcontroller 4 activates the various motors 16 to move a respectiveconnector member 26 via tabs 22 in order to coordinate an operationand/or movement of one or more end effectors 100. Although FIG. 1B showsone end of connector member 26 that is coupled to instrument tab 18 andanother end coupled to end effector 100, in some instances two or moreconnector members 26 or two ends of a single connector member may becoupled to instrument tab 22. For example, in some instances, twoconnector members or connector member ends may be coupled in oppositedirections to a single motor so that as the motor is activated in afirst direction, one of the connector members winds up while the otherconnector member lets out. Other connector member configurations may beused in different embodiments.

Additionally, while FIG. 1B shows drive tab 18 engaging with instrumenttab 22 only on an upper side of drive tab 18 as drive tab 18 moves up alength of drive member 17, other variations are also possible. In someinstances, drive tab 18 may engage with instrument tab 22 on more thanone side (e.g., a top and bottom side) and/or instrument tab 22 mayengage with drive tab 18 on more than one side. Having at least one ofthe tabs 18, 22 engage with the other on more than one side may ensurethat the tabs 18, 22 are locked together so that when drive tab 18 movesup, instrument tab 22 also moves up, and when drive tab 18 moves down,then instrument tab 22 also moves down.

Referring again to FIG. 1A, robot arms 2, 3 may be driven by electricdrives (not shown) that are connected to controller 4. Controller 4(e.g., a computer) is set up to activate the drives, in particular bymeans of a computer program, in such a way that robot arms 2, 3, theirattachment devices 9, 11, and thus, surgical instrument 20 (includingend effector 100) execute a desired movement according to a movementdefined by means of manual input devices 7, 8. Controller 4 may also beset up in such a way that it regulates the movement of robot arms 2, 3and/or of the drives.

Controller 4 can include any suitable logic control circuit adapted toperform calculations and/or operate according to a set of instructions.Controller 4 can be configured to communicate with a remote system “RS,”wirelessly (e.g., Wi-Fi, Bluetooth, LTE, etc.) and/or wired. Remotesystem “RS” can include data, instructions and/or information related tothe various components, algorithms, and/or operations of work station 1.Remote system “RS” can include any suitable electronic service,database, platform, cloud, or the like. Controller 4 may include acentral processing unit operably connected to memory. The memory mayinclude transitory type memory (e.g., RAM) and/or non-transitory typememory (e.g., flash media, disk media, etc.). In some embodiments, thememory is part of, and/or operably coupled to, remote system “RS.”

Controller 4 can include one or more counters to count, for example, anumber of uses of one or more of the components of the medical workstation (e.g., connector members 26, end effector 100, etc.). Controller4 can include a plurality of inputs and outputs for interfacing with thecomponents of work station 1, such as through a driver circuit.Controller 4 can be configured to receive input signals and/or generateoutput signals to control one or more of the various components (e.g.,one or more motors 16) of work station 1. The output signals caninclude, and/or can be based upon, algorithmic instructions which may bepre-programmed and/or input by a user. Controller 4 can be configured toaccept a plurality of user inputs from a user interface (e.g., switches,buttons, touch screen, etc. of operating console 5) which may be coupledto remote system “RS.”

A database 4 a can be directly and/or indirectly coupled to controller4. Database 4 a can be configured to store pre-operative data fromliving being(s) 13 and/or anatomical atlas(es). Database 4 a can includememory which can be part of, and/or or operatively coupled to, remotesystem “RS.”

In some embodiments, the memory of database 4 a (or the like) includesreference data of one or more of any of the components of work station1. In some embodiments, the reference data can be predetermined. Incertain embodiments, the reference data can be measured, created, orstored in real-time. The reference data can include any suitableproperty, characteristic and/or condition of one or more of thecomponents of work station 1. For example, the memory can includetensile data of the one or more connector members 26 such as connectormember strength, elasticity, and/or degradation data applicable to oneor more of connector members 26, a number of uses of one or more ofconnector members 26, and/or an age of one or more of connector members26. In some embodiments, the reference data may include ranges or setsof ranges to which real-time data can be compared and contrasted fordetermining health (e.g., expended and/or remaining lifespan). Thememory of database 4 a may also store a connector member referencecondition, one or more updated connector member conditions, and/or otherdata associated with the stored conditions, such as a date that thecondition was measured, created, or stored.

The work station 1 may support one or more position sensors 19 b andforce sensors 19 a that may be in electrical communication withcontroller 4 and/or remote system “RS.” The sensors 19 a, 19 b may beconfigured to provide an input signal indicative of real-time positionand force data to controller 4. Force sensor 19 a may include a straingauge load cell and/or a piezoelectric load cell. Position sensor 19 bmay include an absolute or incremental position sensor. In someinstances, where positional sensor is configured to measure positioninformation of a rotating object, such as drive member 17 and/or a shaftoutput of motor 16, position sensor 19 b may include a rotary encoder orother sensor that converts an angular position or motion of a rotatingoutput to an analog or digital code. Sensors 19 a, 19 b may beconfigured to measure, sample, and/or transmit positional or forceinformation in real-time at similar intervals so that the data from eachof the sensors 19 a, 19 b coincides with each other.

Controller 4 can be programmed to compare real-time data to referencedata and provide an output signal in response to a comparison of thereal-time data to the reference data. In embodiments, controller 4 canbe configured to communicate with one or more of the motors 16 to adjustthe position of tabs 18, 22, and/or an amount of tension in one or moreof connector members 26 in response to the output signal. In someembodiments, controller 4 may be configured to check whether connectormembers 26 in surgical instrument 20, are associated with any previouslystored reference conditions while surgical instrument 20 is coupled toone of robot arm 2, 3. Controller 4 may then be configured to retrievethe reference conditions form a memory to the extent that such asassociation exists, otherwise controller 4 may be configured to triggerone or more of the aforementioned procedures to generate and then storethe reference condition. Once the reference condition has been generatedand/or retrieved, controller 4 may be configured to further trigger, inresponse to one or more events, one or more of the aforementionedprocedures to generate and/or store an updated condition of connectormember 26. These events can include, for example, an initial and/orsubsequent coupling of the surgical instrument 20 to the robot arm 2, 3;a use count of the surgical instrument 20 that exceeds a thresholdvalue; a user initiated command; and/or an expiration of one or moretime periods.

In general, as illustrated in FIG. 4B, referenced data/information ofthe components of work station 1 (e.g., one or more connector members26) can be stored in memory, for example, on a memory device coupled tomedical work station 1 and/or part of remote system “RS” as describedabove. Such data/information can be stored prior to any use of one ormore components of work station 1. One or more first events, such asthose described above (e.g., generating and storing a reference orupdate condition, a use and/or a number of uses of one or more connectormembers 26), can occur so that real-time data of components of the workstation 1 can be measured. Measurement of the real-time data can bedetermined by virtue of force and position sensors 19 a, 19 b and/orcontroller 4, prior to a use of one or more of the components.

In certain embodiments, reference data of the one or more connectormembers 26 can be compared with measured real-time data of the one ormore connector members 26 to determine the real-time health (e.g.,remaining/expended lifespan) of one or more connector members 26relative to the initial health of one or more connector members 26. Iflifespan/health of one or more of connector members 26 remains or isintact, an output signal may be provided. An occurrence of anotherevent, which may be different and/or the same as the one or more firstevents, may also provide an output signal. If no health/lifespan remainsor is otherwise registered/intact, there may be failure or anunusability of connector members 26, which can require adjustment and/orreplacement of one or more of the components (e.g., connector members,end effector, etc.) of work station 1. The output signal can be anysuitable signal, for example, indicative of health/remaining lifespan(e.g., via number of uses, time period, etc.), if any, and/or failure.An output signal indicative of failure can be generated by controller 4upon a breaking of one or more of connector members 26, or upon alengthening of the one or more connector members 26 beyond predeterminedamount. As can be appreciated, stored pre-determined data may be presetand/or updated periodically, including before, during, and/or after use.

It is contemplated that methods of the present disclosure involvedetermine a tensile change in a connector member based on comparing atension of connector member 26 with a position of a component coupled toconnector member 26. In some embodiments, controller 4 can be configuredto generate/analyze force versus position plots to approximate adegradation of connector member 26.

In some instances, the method may include initially calibrating areference condition in connector member 26, but in other instances thisfeature may have been previously performed, calculated, or estimated.The method can include measuring the real-time data of the one or moreconnector members 26 after one or more uses thereof.

In certain embodiments, the method involves automating an output signalindicative of real-time data of the one or more connector members 26 inresponse to one or more events. The one or more events can include afirst use of the surgical tool, a use of the surgical tool subsequent tothe first use of the surgical tool, and/or an expiration of one or moretime periods.

The method may include receiving an input signal, indicative of a userinput, as an event to initiate an output signal indicative of real-timedata of the one or more connector members 26. The method can involveregistering a failure of the one or more connector members 26 andproviding an output signal indicative of the failure.

Turning now to FIG. 5, one embodiment of an end effector 200 for use inthe medical work station 1 is illustrated. End effector 200 is a wristedsurgical device that uses differential cable tension on four connectormember ends 230 a-230 d of a pair of connector members 231 a, 231 b todrive three primary motion outputs: yawing movement, illustrated byarrow “Y,” pitching movement, illustrated by arrow “P,” and graspingmovement, illustrated by arrow “J.”

End effector 200 includes a mounting member or wrist assembly 210, a jawassembly 220, a connector member assembly 230, and a clevis 240 that areoperatively coupled to medical work station 1.

Wrist assembly 210, which may form part of shaft assembly 21 of surgicalinstrument 20, has a mount body 210 a with a proximal end that couplesto surgical instrument 20 (FIG. 1B). Mount body 210 a extends distallyto a pair of spaced-apart arms including a first arm 210 b and a secondarm 210 c. The pair of spaced-apart arms defines a first pin channel 210d and a second pin channel 210 e that extend transversely through eachof first and second arms 210 b, 210 c. Wrist assembly 210 supports afirst set of idler pulleys 212 and a second set of idler pulleys 214that are aligned with first and second pin channels 210 d, 210 e,respectively, such that the first set of idler pulleys 212 is locatedproximal of second set of idler pulleys 214. First and second sets ofidler pulleys 212, 214 are secured to wrist assembly 210 via first andsecond pulley pins 250 a, 250 b, respectively. Second pulley pin 250 band second set of idler pulleys 214 define a pitch axis “C1” about whichfirst and second jaw members 222, 224 pitch relative to longitudinalaxis “L.”

Jaw assembly 220 includes a first jaw member 222 and a second jaw member224 that are pivotably coupled together. First jaw member 222 includes agrasping portion 222 a that extends distally from a jaw pulley 222 b.Second jaw member 224 includes a grasping portion 224 a that extendsdistally from a jaw pulley 224 b. First and second jaw pulleys 222 b,224 b may be integrally formed with grasping portions 222 a, 224 a,respectively. Grasping portions 222 a, 224 a include respectivetissue-engaging surfaces 222 c, 224 c configured to engage tissue. Firstand second jaw pulleys 222 b, 224 b define respective first and secondconnector member channels 222 d, 224 d configured to receive connectormember assembly 230.

Connector member assembly 230 includes a pair of connector members 231a, 231 b that are routed/wrapped around the sets of idler pulleys 212,214 and jaw pulleys 222 b, 224 b to a plurality of connector memberportions 230 a-230 d. First connector member 231 a of the pair ofconnector members 231 a, 231 b includes a first connector member portion230 a of the plurality of connector member portions 230 a-230 d at oneend thereof and a second connector member portion 230 c of the pluralityof connector member portions 230 a-230 d at a second end thereof. Secondconnector member 231 b of the pair of connector members 231 a, 231 bincludes a third connector member portion 230 b of the plurality ofconnector member portions 230 a-230 d at a first end thereof and afourth connector member portion 230 d of the plurality of connectormember portions 230 a-230 d at a second end thereof. A plurality offerrules 232 (only one being shown) are coupled to the pair of connectormembers 231 a, 231 b to secure the pair of connector members 231 a, 231b to first and second jaw members 222, 224 of jaw assembly 220,respectively. A central portion of first connector member 231 a issecured to jaw pulley 222 b of first jaw member 222 by first one of thepair of ferrules 232 and a central portion of second connector member231 b is secured to jaw pulley 224 b of second jaw member 224 by asecond one of the pair of ferrules 232. Proximal ends of cable memberportions 230 a-230 d are coupled to one or more instrument tabs 22 ofsurgical instrument 22 so that connector member portions 230 a-230 dmove in response to movement of the instrument tabs 22 as describedabove.

For example, as seen in FIGS. 6A-6D, one or more of connector memberportions 230 a-230 d can be moved independently of one or more of theother connector member portions 230 a-230 d and/or simultaneously withone or more of the other connector member portions 230 a-230 d in thesame and/or in opposite directions of one or more of the other connectormember portions 230 a-230 d to effectuate pitching, yawing, and/oropening/closing of jaw assembly 220.

With continued reference to FIGS. 5 and 6A-6D, clevis 240 includes apair of fingers 242, 244 that extend from a base portion 246. Each ofthe pair of fingers 242, 244 is spaced apart from the other andtogether, the pair of fingers 242, 244 defines a pin passage 242 a thatextends therethrough. The base portion 246 is pivotally mounted tosecond set of idler pulleys 214 by pivot pin 250 b to enable jawassembly 220 to pitch/articulate, as indicated by arrow “P,” relative toa longitudinal axis “L” of end effector 200. Jaw pulleys 222 b, 224 b ofjaw assembly 220 are coupled together and mounted between the pair offingers 242, 244 of clevis 240 by pivot pin 250 c. Pivot pin 250 c andjaw pulleys 222 b, 224 b of jaw assembly 220 define yaw and graspingaxes “C2” and “C3,” respectively, which are coincident with each other.Pin passage 242 a receives pivot pin 250 c to enable jaw assembly 220 toyaw about yaw axis “C2” relative to a longitudinal axis “L” of endeffector 200, as indicated by arrow “Y,” and/or open/close jaw assembly220, about grasping axis “C3” as indicated by arrow “J.” With thisarrangement, wrist length is minimized, enabling greater pitch and/oryaw movement while minimizing shaft motion, which, in turn, enablesmultiple instruments to be placed closer together and/or enables fastermanipulation of the end effector.

In use, the pair of connector members 231 a, 231 b, namely the pluralityof connector member portions 230 a-230 d can be pulled and/or releasedby movement of instrument tabs 22, described above, to achieve pitch,yaw, grasping/dissecting and/or any combinations of these motions. Thisdifferential drive arrangement advantageously enables the tension in thepair of connector members 231 a, 231 b to be adjusted and/or relaxed asdesired, for example, to limit load applied to various components of thesurgical system (e.g., connector members, pulleys, tabs, etc.).Furthermore, position and/or force sensors 19 a, 19 b can be utilized toactively monitor output loads, such as grasping force, torque around thepitch axis, and torque around the yaw axis.

In a force feedback test performed in connection with an embodiment ofend effector 200 with a four connector member differential arrangement(see, e.g., connector member portions 230 a, 230 b, 230 c, and 230 d),individual connector member tensions were monitored using a test rigwith independent position control of each connector member portion tocalculate forces at distal tips of a pair of jaw members (see, e.g.,first and second jaw members 222, 224). The test rig included a customjaw set of 17-4 H900 Direct Metal Laser sintered (DMLS) jaws with a loadcell at the tip thereof to evaluate the feasibility of using connectormember tensions of full length tungsten connector members to estimatetip grasping forces “F.” Each jaw member of the jaw set included a jawpulley. Each jaw pulley had the same radius.

Tip forces were then computed by averaging the forces acting on both jawmembers of the jaw set using the following formulas:force of first jaw member (“Jaw1”) of the jaw set(“Jaw1Force”)=[(T3−T1)×radius of one of the jaw pulleys]/length of oneof the jaw members;force of second jaw member (“Jaw2”) of the jaw set(“Jaw2Force”)=[(T4−T2)×radius of one of the jaw pulleys]/length of oneof the jaw members; andcalculated force=[Jaw1Force+Jaw2Force]/2;where T1−T4 correspond to tension applied to connector member portions230 a-230 d, respectively.

To simulate the presence of an external force, Jaw1 and Jaw2 were driveninto each other to develop force data with respect to only the grasp(see FIG. 7A) and with respect to combined grasp and movement (see FIG.7B). As seen in FIGS. 7A and 7B, after running cyclic tests whilevarying jaw, pitch, and yaw angles, the results were then plotted on agraph with respect to the calculated forces. Negative jaw anglesindicated jaw overlap: the greater the negative value, the higher thesimulated force. With respect to FIG. 7B, the graph indicates that thecalculated grasping force tracts the measured jaw force with an increasein the grasping force as the jaw angle is decreased. FIG. 7A shows themeasured versus calculated forces without any pitch and yaw motions asJaw1 and Jaw2 are closed together. Even in this case, the calculatedforce tracks the measured force. There is a positive offset (calculatedforce is greater than measured force) when Jaw1 and Jaw2 are movingcloser to each other (closing). This offset reverses when Jaw1 and Jaw2start moving away from each other (opening). Once the jaw angle isgreater than zero, there is no force recorded by the load cell.

The near perfect tracking of the calculated force shown in FIG. 7B ascompared to the offsets in the calculated force shown in FIG. 7A can beexplained by accounting for friction. In the test, the connector memberswere preloaded to 20 N to increase stiffness in the system. When Jaw1and Jaw2 were driven into each other, the tensions rose up 120 N. Thisconnector member tension pulled Jaw1 and Jaw2 into the pivot pin onwhich Jaw1 and Jaw2 rotate. The normal force between the pivot pin andJaw1 and Jaw2 caused frictional force that opposed applied force. Thedirection of the frictional force changed depending on the direction ofmotion.

Therefore, in the absence of friction:Jaw1Force=Jaw2ForceIn the presence of friction:Jaw1Force=F+f when Jaw1 is driven into Jaw2 BUTJaw1Force=F−f when Jaw1 is in contact with Jaw2 and is driven away fromJaw2Similarly,Jaw2Force=F+f when Jaw2 is driven into Jaw1 BUTJaw2Force=F−f when Jaw2 is in contact with Jaw1 and is driven away fromJaw1Where the combination of yaw motion along with jaw closing causes Jaw 1to move towards Jaw2 while Jaw 2 moves away from Jaw 1:Jaw1Force=F+f and Jaw2Force=F−fComputed Force=(Jaw1Force+Jaw2Force)/2=(F+f+F−f)/2=FThe error in measurement occurs when both Jaw1 and Jaw2 are movingtowards each other or away from each other. The error is +/−f. This 2 frange of error can be observed in the plotted data as the differencebetween the observed and the measure (Max 3 N).

Although accuracy of measured force depends on the overall friction inthe system, taking friction into account, measured and calculated forcestrack one another nearly perfectly in both of the plotted test cases,thereby evidencing the ability to estimate grasping forces by monitoringconnector member tensions.

Persons skilled in the art will understand that the structures andmethods specifically described herein and shown in the accompanyingfigures are non-limiting exemplary embodiments, and that thedescription, disclosure, and figures should be construed merely asexemplary of particular embodiments. It is to be understood, therefore,that the present disclosure is not limited to the precise embodimentsdescribed, and that various other changes and modifications may beeffected by one skilled in the art without departing from the scope orspirit of the disclosure. Additionally, the elements and features shownor described in connection with certain embodiments may be combined withthe elements and features of certain other embodiments without departingfrom the scope of the present disclosure, and that such modificationsand variations are also included within the scope of the presentdisclosure. Accordingly, the subject matter of the present disclosure isnot limited by what has been particularly shown and described.

The invention claimed is:
 1. A method of determining health of at leastone connector member of a robotic surgical system, the at least oneconnector member operably coupled to an end effector of the roboticsurgical system and movable to operate the end effector, the methodcomprising: storing reference data of the at least one connector memberprior to an initial use of the at least one connector member includingan initial linear stretching distance of the at least one connectormember, the at least one connector member having an initial health;measuring real-time data of the at least one connector member subsequentto the initial use of the at least one connector member including asubsequent linear stretching distance of the at least one connectormember; and comparing the reference data of the at least one connectormember with measured real-time data of the at least one connector memberto determine a real-time health of the at least one connector memberrelative to the initial health of the at least one connector member. 2.The method of claim 1, wherein measuring real-time data of the at leastone connector member includes measuring force applied to the at leastone connector member.
 3. The method of claim 1, further includingcalibrating tension in the at least one connector member in response tochanges in the real-time data of the at least one connector member. 4.The method of claim 1, further including automating an output signalindicative of real-time data of the at least one connector member inresponse to at least one event.
 5. The method of claim 1, furtherincluding receiving an input signal indicative of a user input toinitiate an output signal indicative of real-time data of the at leastone connector member.
 6. The method of claim 1, further includingregistering a failure of the at least one connector member and providingan output signal indicative of the failure.
 7. The method of claim 1,further including sending an alert indicating that the at least oneconnector member needs to be replaced.